The EEG at different stages of acute secondary traumatic midbrain and bulbar brain syndromes.

One hundred and thirty EEGs were analysed from 113 patients with acute secondary traumatic midbrain and bulbar brain syndromes. The EEG pattern was related to the stage of the midbrain syndrome caused by supratentorial brain shift. A decrease in the number of different EEG patterns was associated with increasing intracranial pressure. Unfavourable prognosis was indicated by the disappearance of sleep or sleep-like activities alternating pattern and loss of reactivity. Lateralization by the EEG proved to be superior to clinical findings in full stages of the midbrain syndrome. EEG abnormalities due to the herniation itself interfered with EEG changes due to secondary circulatory, respiratory and metabolic encephalopathies. In such cases, the above mentioned regularities were blurred.